Electrical power distribution busway systems are typically used to distribute electrical power throughout buildings, particularly commercial or industrial type buildings. Generally, the busway includes a number of busway sections which are connected to one another by busway joints. Each busway section includes a housing that encloses a plurality of busbars which may be phase busbars, neutral busbars, or ground busbars depending on the particular application. High current (high-amp) busway systems generally have current carrying capacity of 600 to 5000 amperes, while low current (low-amp) generally have current carrying capacity of 200 to 800 amperes.
The machines, lights, tools and other components requiring electricity are provided access to the power conducting busbars at various power tap-off locations disposed along the busway. An opening is typically provided through the housing at each power tap-off location and the conductive material of the busbars is exposed for connection with a bus plug connector. The bus plug generally includes an electrical housing containing one or more breakers and a disconnect switch. A mechanical connector is provided for mechanically attaching the bus plug to the busway. An electrical connector extends from the bus plug through a window in the busway housing. A door on the bus plug housing provides access to the interior of the housing.
Electrical standards require an interlock mechanism to prevent the bus plug door from being opened when the disconnect switch is in the "power on" position and to prevent the power from being turned on when the door is open. Typically, prior art designs could be defeated by partially opening the bus plug door, forcing the power on and then fully opening the bus plug door.
Accordingly, it would be advantageous to provide a bus plug door interlock mechanism that may not be defeated by forcing the power on while the bus plug door is partially opened.